Display device and electronic apparatus

ABSTRACT

A display device includes: a pixel array unit having pixels including a circuit configuration, in which a first electrode of an electro-optical element and a source electrode of a driving transistor are connected together, a gate electrode of the driving transistor and a source electrode or a drain electrode of a writing transistor are connected together, a holding capacitor is connected between the gate electrode and the source electrode, and an auxiliary capacitor is connected between the first electrode and a second electrode, disposed in a matrix shape. A signal line used for transmitting a video signal is disposed between adjacent pixels, and from one pixel of adjacent pixels to an area of the other pixel, the auxiliary capacitor of the one pixel is set to be disposed. One electrode of the auxiliary capacitor disposed on the signal line side is conductive with the second electrode of the electro-optical element.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent ApplicationNo. JP 2009-007344 filed in the Japanese Patent Office on Jan. 16, 2009,the entire content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device and an electronicapparatus, and more particularly, to a flat type (flat panel type)display device and an electronic apparatus formed by disposing pixelsincluding electro-optical elements in a matrix form.

2. Description of the Related Art

Recently, in the field of display devices that perform image display,flat type display devices formed by disposing pixels (pixel circuits)including light emitting elements in a matrix form have been spreadingrapidly. As the flat type display devices, organic EL display devicesusing organic EL (electroluminescence) elements that utilize aphenomenon of light emission at the time of applying an electric field,for example, to an organic thin film have been developed andcommercialized.

The organic EL display device has the following features. The organic ELelement can be driven by an application voltage of 10 V or less, andthus has low power consumption. In addition, since the organic ELelement is a self-luminous element, the organic EL display does not needa light source (back light) that may be essential to a liquid crystaldisplay device. In addition, the response speed of the organic ELelement is very high with response time of several microseconds, andaccordingly, no afterimage occurs at the time of displaying a motionpicture.

Similarly to the liquid crystal display device, a simple (passive)matrix type or an active matrix type may be used as a driving method ofthe organic EL display device. Recently, active matrix-type displaydevices in which an active element such as an insulated gate-type fieldeffect transistor (generally, TFT (thin film transistor)) is disposed ina pixel circuit have been actively developed.

It is generally known that the I-V characteristics (current-voltagecharacteristics) of the organic EL element degrade as time elapses(so-called degradation over time). In addition, a threshold voltage Vthof a driving transistor or the mobility μ of a semiconductor thin filmthat configures a channel of the driving transistor (hereinafter,described as “mobility of a driving transistor”) changes over time ormay be different for each pixel due to a deviation in the manufacturingprocess thereof.

Accordingly, in order to maintain emission luminance of the organic ELelement to be constant without being affected by the above-describedfactors, a configuration in which a compensation function forcharacteristic variances in the organic EL element and correctionfunctions including a correction function for variances in the thresholdvoltage Vth of the driving transistor (hereinafter, described as“threshold value correction”) or a correction function for variances inthe mobility μ of the driving transistor are included in each pixelcircuit has been used (for example, see JP-A-2006-133542).

SUMMARY OF THE INVENTION

Here, in a pixel layout in related art, pixels are disposed such thatthe TFT layout area is asymmetric in accordance with the size (constant)of each pixel circuit. On the other hand, second wirings are disposed atan equal pitch. Thus, when the size of a constituent element of aspecific pixel is larger than that of a different pixel so as toincrease the layout density thereof, a part of the constituent elementhaving high layout density is disposed in a space of a pixel having lowlayout density. In such a case, polysilicon that forms a middle layerpasses below a video signal line that is a second wiring disposedbetween pixels. In a case where the electric potential of thepolysilicon is the anode electric potential, there is a problem that adecrease in the luminance occurs due to capacitive coupling that iscaused by parasitic capacitance generated between the video signal lineand the anode.

Therefore, there is a need for providing technology for preventing adecrease in the luminance due to capacitive coupling by evadingformation of parasitic capacitance between a video signal line and ananode.

According to an embodiment of the present invention, there is provided adisplay device including: a pixel array unit having pixels including acircuit configuration, in which a first electrode of an electro-opticalelement and a source electrode of a driving transistor are connectedtogether, a gate electrode of the driving transistor and a sourceelectrode or a drain electrode of a writing transistor are connectedtogether, a holding capacitor is connected between the gate electrodeand the source electrode of the driving transistor, and an auxiliarycapacitor is connected between the first electrode and a secondelectrode of the electro-optical element, disposed in a matrix shape. Asignal line used for transmitting a video signal is disposed betweenadjacent pixels, and, from one pixel of adjacent pixels to an area ofthe other pixel, the auxiliary capacitor of the one pixel is set to bedisposed, and one electrode of the auxiliary capacitor that is disposedon the signal line side is conductive with the second electrode of theelectro-optical element. The embodiment of the invention also providesan electronic apparatus that has the above-described display devicedisposed in a main body casing.

According to the above-described embodiments of the present invention,by using a configuration in which the auxiliary capacitor is disposed inan adjacent pixel through the lower side of the signal line used fortransmitting a video signal, one electrode, which is disposed on thesignal line side, of the electrodes of the auxiliary capacitor isallowed to be conductive with the second electrode of theelectro-optical element. In other words, of the electrodes of theauxiliary capacitor, one electrode disposed on the signal line side hasthe cathode electric potential, and the other electrode of the auxiliarycapacitor has the anode electric potential. Accordingly, an area betweenthe signal line and the anode electric potential is shielded by thecathode electric potential, whereby formation of parasitic capacitancebetween the signal line and the anode is prevented.

According to the embodiment of the invention, in a circuit configuring apixel, by avoiding formation of parasitic capacitance between a signalline and an anode, a decrease in the luminance due to capacitivecoupling can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a system configuration that representsan active-matrix type organic EL display device that serves as a premiseof an embodiment of the present invention.

FIG. 2 is a circuit diagram representing a concrete example of theconfiguration of a pixel (pixel circuit).

FIG. 3 is a timing waveform chart for illustrating the operation of anorganic EL display device of the active matrix type that serves as apremise of an embodiment of the invention.

FIGS. 4A to 4D are explanatory diagrams (first example) illustrating thecircuit operation of an organic EL display device of the active matrixtype that serves as a premise of an embodiment of the invention.

FIGS. 5A to 5D are explanatory diagrams (second example) illustratingthe circuit operation of an organic EL display device of the activematrix type that serves as a premise of an embodiment of the invention.

FIGS. 6A to 6C are explanatory diagrams (third example) illustrating thecircuit operation of an organic EL display device of the active matrixtype that serves as a premise of an embodiment of the invention.

FIG. 7 is a schematic plan view illustrating a pixel structure inrelated art.

FIG. 8 is a cross-sectional view taken along line A-A shown in FIG. 7.

FIG. 9 is an equivalent circuit of a pixel unit of the pixel structurerepresented in FIG. 7.

FIG. 10 is a timing chart illustrating the operation of a circuitdiagram represented in FIG. 9.

FIG. 11 is a diagram of the system configuration representing oneexample of this embodiment.

FIG. 12 is a schematic plan view illustrating the pixel structureaccording to this embodiment.

FIG. 13 is a schematic cross-sectional view taken along line B-B shownin FIG. 12.

FIG. 14 is a schematic cross-sectional view taken along line C-C shownin FIG. 12.

FIG. 15 is a timing chart illustrating the operation of the pixelconfiguration according to this embodiment.

FIG. 16 is a perspective view showing the outer appearance of atelevision set to which this embodiment is applied.

FIGS. 17A and 17B are perspective views showing the outer appearance ofa digital camera to which this embodiment is applied. FIG. 17A is aperspective view viewed from the front side, and FIG. 17B is aperspective view viewed from the rear side.

FIG. 18 is a perspective view showing the outer appearance of a notebookpersonal computer to which this embodiment is applied.

FIG. 19 is a perspective view showing the outer appearance of a videocamera to which this embodiment is applied.

FIGS. 20A to 20G are diagrams showing the outer appearances of acellular phone, to which this embodiment is applied. FIG. 20A is a frontview in an open state, FIG. 20B is a side view thereof, FIG. 20C is afront view in a closed state, FIG. 20D is a left side view, FIG. 20E isa right side view, FIG. 20F is a top view, and FIG. 20G is a bottomview.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the present invention (hereinafter,referred to as an “embodiment”) will be described. The descriptionthereof will be followed in the following order.

1. Display Device (System Configuration, Pixel Circuit, and CircuitOperation) As Premise of This Embodiment

2. Problem in Pixel Structure in Related Art (Layout of Pixel Circuit,Equivalent Circuit, and Timing Chart)

3. Configuration Example According to This Embodiment (SystemConfiguration, Wiring Structure, and Timing Chart)

4. Applications (Various Applications to Electronic Apparatuses)

1. Display Device (System Configuration, Pixel Circuit, and CircuitOperation) as Premise of this Embodiment System Configuration

FIG. 1 is a schematic diagram of a system configuration that representsan active-matrix type display device serves as a premise of thisembodiment.

Here, as an example, an organic EL display device of an active-matrixtype that uses an electro-optical element of a current-driven type ofwhich emission luminance changes in accordance with the value of acurrent flowing through the device such as an organic EL element(organic electroluminescence element) as a light emitting element willbe described.

As represented in FIG. 1, an organic EL display device 100 has aconfiguration including a pixel array unit 102 formed bytwo-dimensionally disposing pixels (PXLC) 101 in a matrix shape and adriving unit that is disposed on the periphery of the pixel array unit102 and drives each pixel 101. As the driving unit that drives thepixels 101, for example, a horizontal driving circuit 103, a writingscanning circuit 104, and a power supply scanning circuit 105 aredisposed.

In the pixel array unit 102, in the pixel array of m rows and n columns,scanning lines WSL-1 to WSL-m and power supply lines DSL-1 to DSL-m arewired for each pixel row, and signal lines DTL-1 to DTL-n are wired foreach pixel column.

The pixel array unit 102, generally, is formed on a transparentinsulating substrate such as a glass substrate and has a flat-type panelstructure. Each pixel 101 of the pixel array unit 102 may be formed byan amorphous silicon TFT (thin film transistor) or a low-temperaturepoly silicon TFT. When the low-temperature polysilicon TFT is used, thehorizontal driving circuit 103, the writing scanning circuit 104, andthe power supply scanning circuit 105 can also be mounted on a displaypanel (substrate) that forms the pixel array unit 102.

The writing scanning circuit 104 is configured by a shift register thatsequentially shifts (transmits) start pulses sp in synchronization witha clock pulse ck or the like. The writing scanning circuit 104 suppliespulses (scanning signals) WS1 to WSm by sequentially writing the pulsesinto the scanning lines WSL-1 to WSL-m when a video signal is writteninto each pixel 101 of the pixel array unit 102, whereby sequentiallyscanning (line sequential scanning) the pixels 101 of the pixel arrayunit 102 in units of one row.

The power supply scanning circuit 105 is configured by a shift registerthat sequentially shifts the start pulses sp in synchronization with theclock pulse ck or the like. The power supply scanning circuit 105selectively supplies power supply line electric potentials DS1 to DSmthat are shifted between a first electric potential Vcc_H and a secondelectric potential Vcc_L lower than the first electric potential Vcc_Hto the power supply lines DSL-1 to DSL-m in synchronization with linesequential scanning performed by the writing scanning circuit 104.Accordingly, the power supply scanning circuit 105 controls emission ornon-emission of the pixels 101.

The horizontal driving circuit 103 appropriately selects either a signalvoltage Vsig of a video signal (hereinafter, it may be also referred toas only a “signal voltage”) corresponding to luminance information thatis supplied from a signal supply source (not shown) or a signal linereference electric potential Vo so as to be written into the pixels 101of the pixel array unit 102 through the signal lines DTL-1 to DTL-n, forexample, in units of one row. In other words, the horizontal drivingcircuit 103 employs a driving form of the line sequential writing typein which a signal voltage Vin of a video signal is written in units ofone row (line).

Here, the signal line reference electric potential Vo is a voltage (forexample, a voltage corresponding to a black level) that becomes areference for the signal voltage Vin of the video signal. In addition,the second electric potential Vcc_L is set to an electric potential thatis lower than the signal line reference electric potential Vo, forexample, an electric potential that is lower than “Vo−Vth” wherein athreshold voltage of a driving transistor is denoted by Vth. Morepreferably, the second voltage Vcc_L is set to an electric potentialthat is sufficiently lower than “Vo−Vth”.

Pixel Circuit

FIG. 2 is a circuit diagram representing a concrete example of theconfiguration of the pixel (pixel circuit).

As shown in FIG. 2, the pixel 101 has a pixel configuration in which anelectro-optical element of the current-driven type, in which theemission luminance changes in accordance with the value of a currentflowing through the device, for example, an organic EL element 1D isincluded as a light emitting element, and a driving transistor 1B, awriting transistor 1A, and a holding capacitor 1C are included inaddition to the organic EL element 1D. In other words, the pixel 101 hasa 2Tr/1C pixel configuration that is configured by two transistors (Tr)and one capacitor (C).

In the pixel 101 having such a configuration, N-channel TFTs are used asthe driving transistor 1B and the writing transistor 1A. However, thecombination of conductive types of the driving transistor 1B and thewriting transistor 1A described here is merely an example, and anembodiment of the invention is not limited to such a combination.

The organic EL element 1D has a cathode electrode connected to a commonpower supply line 1H that is wired commonly to all the pixels 101. Thedriving transistor 1B has a source electrode connected to the anodeelectrode of the organic EL element 1D and a drain electrode connectedto the power supply lines DSL (DSL-1 to DSL-m).

The writing transistor 1A has a gate electrode connected to the scanningline WSL (WSL-1 to WSL-m), one electrode (a source electrode or a drainelectrode) connected to the signal line DTL (DTL-1 to DTL-n), and theother electrode (the drain electrode or the source electrode) connectedto the gate electrode of the driving transistor 1B.

The holding capacitor 1C has one electrode connected to the gateelectrode of the driving transistor 1B and the other electrode connectedto the source electrode of the driving transistor 1B (the anodeelectrode of the organic EL element 1D). In addition, an auxiliarycapacitor 1J has one electrode connected to the anode electrode of theorganic EL element 1D and the other electrode connected to the cathodeelectrode of the organic EL element 1D.

In the pixel 101 having the 2Tr/1C pixel configuration, the writingtransistor 1A is in a conducting state in response to a scanning signalWS applied to the gate electrode from the writing scanning circuit 104through the scanning line WSL. Accordingly, the writing transistor 1Asamples a signal voltage Vin of a video signal corresponding to theluminance information supplied from the horizontal driving circuit 103through the signal line DTL or the signal line reference electricpotential Vo so as to be written into the pixel 101.

The written signal voltage Vin or the signal line reference electricpotential Vo is applied to the gate electrode of the driving transistor1B, and is maintained in the holding capacitor 1C. When the electricpotential DS of the power supply line DSL (DSL-1 to DSL-m) is the firstelectric potential Vcc_H, the driving transistor 1B is supplied with acurrent from the power supply line DSL and supplies a driving currenthaving a current value corresponding to the voltage value of the signalvoltage Vin maintained in the holding capacitor 1C to the organic ELelement 1D, whereby driving the organic EL element 1D by the current soas to emit light.

Circuit Operation of Organic EL Display Device

Next, the circuit operation of the organic EL display device 100 havingthe above-described configuration will be described based on a timingwaveform chart represented in FIG. 3 with reference to operationexplanatory diagrams represented in FIGS. 4A to 6C. Incidentally, in theoperation explanatory diagrams represented in FIGS. 4A to 6C, thewriting transistor 1A is denoted by the symbol of a switch in order tosimplify the drawings. In addition, since the organic EL element 1D hasa capacitance component, an EL capacitance 1I is also shown in thediagrams.

The timing waveform chart represented in FIG. 3 shows changes in theelectric potential (writing pulse) WS of the scanning line WSL (WSL-1 toWSL-m), changes in the electric potential DS (Vcc_H and Vcc_L) of thepower supply line DSL (DSL-1 to DSL-m), and changes in the gate electricpotential Vg and the source electric potential Vs of the drivingtransistor 1B.

Emission Period

The organic EL element 1D is in a light emitting state before time t1 inthe timing waveform chart of FIG. 3 (emission period). During thisemission period, the electric potential DS of the power supply line DSLis the first electric potential Vcc_H, and the writing transistor 1A isin a non-conducting state.

At this moment, since the driving transistor 1B is set to operate in asaturation region, as shown in FIG. 4A, a driving current(drain-to-source current) Ids corresponding to the gate-to-sourcevoltage Vgs of the driving transistor 1B is supplied from the powersupply line DSL through the driving transistor 1B to the organic ELelement 1D. Accordingly, the organic EL element 1D emits light at aluminance level corresponding to the value of the current of the drivingcurrent Ids.

Threshold Value Correction Preparatory Period

Then, a new field of line-sequential scanning begins at time t1. Thus,as shown in FIG. 4B, the electric potential DS of the power supply lineDSL changes from the first electric potential (hereinafter referred toas a “high electric potential”) Vcc_H to the second electric potential(hereinafter, referred to as a “low electric potential”) Vcc_L that issufficiently lower than the signal line reference voltage Vo−Vth of thesignal line DTL.

Here, letting Ve1 be the threshold voltage of the organic EL element 1Dand Vcath be the electric potential of the common power supply line 1H,when the low electric potential Vcc_L satisfies the relation ofVcc_L<Ve1+Vcath, the source electric potential Vs of the drivingtransistor 1B is substantially equal to the low electric potentialVcc_L, and thus the organic EL element 1D is set to be in areverse-biased state and quenched.

Next, at time t2, as the electric potential WS of the scanning line WSLmakes a transition from a low electric potential side to a high electricpotential side, as shown in FIG. 4C, the writing transistor 1A is set ina conducting state. At this moment, since the signal line referenceelectric potential Vo is supplied from the horizontal driving circuit103 to the signal line DTL, the gate electric potential Vg of thedriving transistor 1B becomes the signal line reference electricpotential Vo. The source electric potential Vs of the driving transistor1B is the electric potential Vcc_L that is sufficiently lower than thesignal line reference electric potential Vo.

At this moment, the gate-to-source voltage Vgs of the driving transistor1B is Vo−Vcc_L. Here, when Vo−Vcc_L is not higher than the thresholdvoltage Vth of the driving transistor 1B, a threshold value correctingoperation to be described later may not be performed. Accordingly, theelectric potential relation may need to be set such that Vo−Vcc_L>Vth.As described above, an initialization operation of respectively fixing(determining) the gate electric potential Vg and the source electricpotential Vs of the driving transistor 1B to the signal line referenceelectric potential Vo and the low electric potential Vcc_L is athreshold value correction preparatory operation.

Threshold Value Correcting Period for First Time

Next, as shown in FIG. 4D, when the electric potential DS of the powersupply line DSL shifts from the low electric potential Vcc_L to the highelectric potential Vcc_H at time t3, the source electric potential Vs ofthe driving transistor 1B starts to rise, and a threshold valuecorrecting period for the first time starts. During the threshold valuecorrecting period for the first time, the source electric potential Vsof the driving transistor 1B rises. Accordingly, the gate-to-sourcevoltage Vgs of the driving transistor 1B becomes a predeterminedelectric potential Vx1, and the electric potential Vx1 is maintained atthe holding capacitor 1C.

Subsequently, at time t4 that is start of a latter part of thehorizontal period (1H), as shown in FIG. 5A, the signal voltage Vin ofthe video signal is supplied to the signal line DTL from the horizontaldriving circuit 103, whereby the electric potential of the signal lineDTL makes a transition from the signal line reference electric potentialVo to the signal voltage Vin. During this period, writing signalvoltages Vin into pixels of another row is performed.

At this moment, in order not to write the signal voltage Vin into pixelsof the current row, the electric potential WS of the scanning line WSLis allowed to make a transition from the high electric potential side tothe low electric potential side, whereby the writing transistor 1A is tobe in a non-conducting state. Accordingly, the gate electrode of thedriving transistor 1B is cut off from the signal line DTL to be in afloating state.

Here, when the gate electrode of the driving transistor 1B is in thefloating state, the holding capacitor 1C is connected between the gateand the source of the driving transistor 1B. Thus, when the sourceelectric potential Vs of the driving transistor 1B changes, the gateelectric potential Vg of the driving transistor 1B also changes inaccordance (follow) with the change in the source electric potential Vs.This is a bootstrap operation that is performed by the holding capacitor1C.

Also after time t4, the source electric potential Vs of the drivingtransistor 1B continues to rise so as to rise by Va1 (Vs=Vo−Vx1+Va1). Atthis moment, the gate electric potential Vg also rises by Va1 inaccordance with the rise in the source electric potential Vs of thedriving transistor 1B by the bootstrap operation (Vg=Vo+Va1).

Threshold Value Correcting Period for Second Time

When the next horizontal period begins at time t5, as shown in FIG. 5B,the electric potential WS of the scanning line WSL shifts from the lowelectric potential side to the high electric potential side, and thewriting transistor 1A is in the conducting state. Simultaneously, thesignal line reference electric potential Vo instead of the signalvoltage Vin is supplied to the signal line DTL from the horizontaldriving circuit 103, and a threshold value correcting period for thesecond time begins.

During the threshold value correcting period for the second time, thewriting transistor 1A is in the conducting state, and thus the signalline reference electric potential Vo is written. Accordingly, the gateelectric potential Vg of the driving transistor 1B is initialized backto the signal line reference electric potential Vo. The source electricpotential Vs drops in accordance with a drop in the gate electricpotential Vg at that moment. Then, again, the source electric potentialVs of the driving transistor 1B starts to rise.

Then, as the source electric potential Vs of the driving transistor 1Brises during the threshold value correcting period for the second time,the gate-to-source voltage Vgs of the driving transistor 1B becomes apredetermined electric potential Vx2, and this electric potential Vx2 ismaintained in the holding capacitor 1C.

Subsequently, at time t6 when a latter part of this horizontal periodbegins, as shown in FIG. 5C, as the signal voltage Vin of the videosignal is supplied from the horizontal driving circuit 103 to the signalline DTL, the electric potential of the signal line DTL is allowed tomake a transition from the offset voltage V0 to the signal voltage Vin.During this period, the signal voltage Vin is written into pixels ofanother row (the next row of the row being written at the previoustime).

At this moment, in order not to perform writing the signal voltage Vininto the pixels of the current row, the electric potential WS of thescanning line WSL is allowed to make a transition from the high electricpotential side to the low electric potential side, whereby the writingtransistor 1A is in the non-conducting state. Accordingly, the gateelectrode of the driving transistor 1B is cut off from the signal lineDTL to be in a floating state.

Also after time t6, the source electric potential Vs of the drivingtransistor 1B continues to rise so as to rise by Va2 (Vs=Vo−Vx1+Va2). Atthis moment, by the bootstrap operation, the gate electric potential Vgrises by Va2 in accordance with a rise in the source electric potentialVs of the driving transistor 1B (Vg=Vo+Va2).

Threshold Value Correcting Period for Third Time

The next horizontal period begins at time t7, and, as shown in FIG. 5D,the electric potential WS of the scanning line WSL is allowed to make atransition from the low electric potential side to the high electricpotential side, whereby the writing transistor 1A is in the conductingstate. Simultaneously, the signal line reference electric potential Voinstead of the signal voltage Vin is supplied to the signal line DTLfrom the horizontal driving circuit 103, and a threshold valuecorrecting period for the third time begins.

During this threshold value correcting period for the third time, as thewriting transistor 1A is in the conducting state, the signal linereference electric potential Vo is written. Accordingly, the gateelectric potential Vg of the driving transistor 1B is reinitialized tothe signal line reference voltage Vo. In accordance with a drop in thegate electric potential Vg at that moment, the source electric potentialVs drops. Then, the source electric potential Vs of the drivingtransistor 1B starts to rise again.

As the source electric potential Vs of the driving transistor 1B rises,finally, the gate-to-source voltage Vgs of the driving transistor 1Bconverges at the threshold voltage Vth of the driving transistor 1B,whereby a voltage corresponding to the threshold voltage Vth ismaintained in the holding capacitor 1C.

By performing the above-described threshold value correcting operationsfor three times, the threshold voltage Vth of the driving transistor 1Bof each pixel is detected, and a voltage corresponding to the thresholdvoltage Vth is maintained in the holding capacitor 1C. In addition,during the threshold value correcting period for the three times, inorder to allow a current to flow not to the organic EL element 1D sidebut only to the holding capacitor 1C side, the electric potential Vcathof the common power supply line 1H is set such that the organic ELelement 1D is in the cut-off state.

Signal Writing Period and Mobility Correcting Period

Next, at time t8, as the electric potential WS of the scanning line WSLis allowed to make a transition to the low electric potential side, asshown in FIG. 6A, the writing transistor 1A is in the non-conductingstate. Simultaneously, the electric potential of the signal line DTL isshifted from the offset voltage V0 to the video voltage Vin of the videosignal.

As the writing transistor 1A is in the non-conducting state, the gateelectrode of the driving transistor 1B is in a floating state. However,since the gate-to-source voltage Vgs is equal to the threshold voltageVth of the driving transistor 1B, the driving transistor 1B is in thecut-off state. Accordingly, a drain-to-source current Ids does not flowin the driving transistor 1B.

Subsequently, at time t9, as the electric potential WS of the scanningline WSL is allowed to make a transition to the high electric potentialside, as shown in FIG. 6B, the writing transistor 1A is in theconducting state. Thus, the signal voltage Vin of the video signal issampled so as to be written into the pixel 101. By writing the signalvoltage Vin by using the writing transistor 1A, the gate electricpotential Vg of the driving transistor 1B becomes the signal voltageVin.

Then, when the driving transistor 1B is driven in accordance with thesignal voltage Vin of the video signal, the threshold voltage Vth of thedriving transistor 1B is offset by the threshold voltage Vth maintainedin the holding capacitor 1C, whereby the threshold value correction isperformed.

At this moment, since the organic EL element 1D is in the first cutoffstate (high impedance state), a current (drain-to-source current Ids)flowing from the power supply line DSL to the driving transistor 1B inaccordance with the signal voltage Vin of the video signal flows in theEL capacitance 1I of the organic EL element 1D, whereby charging of theEL capacitance 1I is started.

By charging the EL capacitance 1I, the source electric potential Vs ofthe driving transistor 1B rises over time. At this moment, since thedeviation of the threshold voltage Vth of the driving transistor 1B hasbeen already corrected (corrected for the threshold value), thedrain-to-source current Ids of the driving transistor 1B depends on themobility μ of the driving transistor 1B.

Finally, when the source electric potential Vs of the driving transistor1B rises up to the electric potential of “Vo−Vth+ΔV”, the gate-to-sourcevoltage Vgs of the driving transistor 1B becomes “Vin+Vth−ΔV”. In otherwords, an increase amount ΔV of the source electric potential Vs acts tobe subtracted from the voltage (Vin+Vth−ΔV) maintained in the holdingcapacitor 1C, that is, to discharge electric charges charged in theholding capacitor 1C for applying a negative feedback. Accordingly, theincrease amount ΔV of the source electric potential Vs becomes thefeedback amount of the negative feedback.

As described above, by applying the drain-to-source current Ids flowingthrough the driving transistor 1B to the gate input of the drivingtransistor 1B, that is, the gate-to-source voltage Vgs as a negativefeedback, mobility correction, in which the dependence of thedrain-to-source current Ids of the driving transistor 1B on the mobilityμ is eliminated, in other words, the deviation of the mobility μ foreach pixel is corrected, is performed.

In particular, the higher the signal voltage Vin of the video signal is,the larger the drain-to-source current Ids becomes, and thus theabsolute value of the feedback amount (correction amount) ΔV of thenegative feedback is increased. Accordingly, the mobility correction isperformed in accordance with the emission luminance level. In addition,when the signal voltage Vin of the video signal is constant, theabsolute value of the feedback amount ΔV for the negative feedback isincreased as the mobility μ of the driving transistor 1B is higher.Accordingly, the deviation of the mobility μ for each pixel can beeliminated.

Emission Period

Next, at time t10, as the electric potential WS of the scanning line WSLmakes a transition to the low electric potential side as shown in FIG.6C, the writing transistor 1A is in a non-conducting state. Accordingly,the gate electrode of the driving transistor 1B is cut off from thesignal line DTL so as to be in a floating state.

As the gate electrode of the driving transistor 1B is in the floatingstate, and simultaneously, the drain-to-source current Ids of thedriving transistor 1B starts to flow through the organic EL element 1D,the anode electric potential of the organic EL element 1D rises inaccordance with the drain-to-source current Ids of the drivingtransistor 1B.

The rise in the anode electric potential of the organic EL element 1D isnot different from a rise in the source electric potential Vs of thedriving transistor 1B. As the source electric potential Vs of thedriving transistor 1B rises, the gate electric potential Vg of thedriving transistor 1B also rises by the bootstrap operation of theholding capacitor 1C.

At this time, assuming that a bootstrap gain is one (ideal value), theamount of the rise in the gate electric potential Vg is equal to that inthe source electric potential Vs. Thus the gate-to-source voltage Vgs ofthe driving transistor 1B is maintained to be constant at Vin+Vth−ΔVduring the emission period. Then, at time t11, the electric potential ofthe signal line DTL shifts from the signal voltage Vin of the videosignal to the signal line reference electric potential Vo.

As is apparent from the description of the operation as above, in thisexample, the threshold value correcting period is set to be over a totalof 3H periods including a 1H period, in which signal writing andmobility correction are performed, and 2H periods that precedes the 1Hperiod. Accordingly, a sufficient time can be acquired as the thresholdvalue correcting period. Therefore, the threshold voltage Vth of thedriving transistor 1B can be correctly detected and maintained in theholding capacitor 1C, whereby the threshold value correcting operationcan be assuredly performed.

Here, the threshold value correcting period is set over the 3H periods.However, this is only an example. Thus, as long as a sufficient time canbe acquired by a 1H period, in which signal writing and mobilitycorrection are performed, as the threshold value correcting period, thethreshold value correcting period may not need to be set over thepreceding horizontal periods. On the other hand, when it is difficult toacquire a sufficient time by setting the threshold value correctingperiod to be over 3H periods in a case where a 1H period is shortened inaccordance with an increase in the precision, the threshold valuecorrecting period may be set over 4H periods or more.

2. Problem in Pixel Structure in Related Art Layout of Pixel Circuit

FIG. 7 is a schematic plan view illustrating a pixel structure inrelated art. FIG. 7 represents the disposition configuration of an R(red) pixel, a G (green) pixel, and a B (blue) pixel. Each pixel isconfigured between the power supply line DSL and the scanning line WSLthat extend in the horizontal direction (horizontal direction in thefigure), and areas of the RGB pixels are partitioned by signal lines DTLthat extend in the vertical direction (the vertical direction in thefigure).

Within the area of each pixel, a writing transistor 1A, a drivingtransistor 1B, and a holding capacitor 1C are disposed. In addition, anauxiliary capacitor 1J that is used for adjusting a writing gain or amobility correcting time is also disposed.

In the example represented in FIG. 7, a case is shown where the patterndensity of the G (green) pixel is lower than that of the R (red) pixel,and the pattern density of the B (blue) pixel is higher than that of theR (red) pixel.

The signal lines DTL-R, DTL-G, and DTL_B are disposed at an equal pitchin the viewpoint of reflection of external light. Thus, a part of theauxiliary capacitor 1J that is a constituent element of the B (blue)pixel is configured to be set in the area of an adjacent G (green)pixel.

Here, the writing transistor 1A, the gate electrode of the drivingtransistor 1B, a lower electrode of the holding capacitor 1C that isconductive with the gate electrode, and a lower electrode of theauxiliary capacitor 1J that is conductive with the cathode electrode ofthe organic EL element are formed as a first wiring layer.

The power supply line DSL, the signal line DTL, and the scanning lineWSL are formed as a second wiring layer. In addition, an intersectionportion of the power supply line DSL and the signal line DTL and anintersection portion of the signal line DTL and the scanning line WSLare switched over to the first wiring layer through a contact hole.

In addition, the writing transistor 1A, the source and drain electrodesof the driving transistor 1B, the upper electrode of the holdingcapacitor 1C that is conductive with the source electrode of the drivingtransistor 1B (the anode electrode of the organic EL element), and theupper electrode of the auxiliary capacitor 1J are formed of polysilicon.The polysilicon is a middle layer that is disposed between the firstwiring layer and the second wiring layer.

FIG. 8 is a schematic cross-sectional view taken along line A-A shown inFIG. 7. The pixel structure includes the first wiring layer M1, thesecond wiring layer M2, and the middle layer MD formed of polysiliconthat are disposed on a glass substrate. As described above, a part ofthe auxiliary capacitor 1J of the B (blue) pixel is set to be in thearea of the adjacent G (green) pixel. Thus, below the signal line DTL-B,an upper electrode D1 of the auxiliary capacitor 1J that is formed ofpolysilicon is disposed. In addition, since the upper electrode D1 isthe same node as the upper electrode of the holding capacitor 1C of theB (blue) pixel, the upper electrode D1 is arranged commonly with theupper electrode of the holding capacitor 1C of the B pixel.

Equivalent Circuit

FIG. 9 is an equivalent circuit of a pixel unit of the pixel structurerepresented in FIG. 7. The signal line DTL is connected to the writingtransistor 1A, and the source electrode or the drain electrode of thewriting transistor 1A is connected to the gate electrode (node g) of thedriving transistor 1B.

To the drain electrode of the driving transistor 1B, the power supplyline DSL is connected, and the holding capacitor 1C is connected betweenthe gate electrode and the source electrode. The source electrode of thedriving transistor 1B is connected to the anode electrode of the organicEL element 1D. In addition, the auxiliary capacitor 1J is connectedbetween the anode and cathode electrodes of the organic EL element 1D.

In the above-described circuit, the signal line DTL configured as thesecond wiring layer and the anode electrode (node s) of the organic ELelement 1D, which is formed of polysilicon, configured as the middlelayer form a parallel plate capacitor, whereby parasitic capacitance Cpis formed therein.

Timing Chart

FIG. 10 is a timing chart illustrating the operation of the circuitdiagram represented in FIG. 9. In the figure, waveforms denoted bybroken lines represent original variances in the electric potential, andsolid lines represent variances in the electric potential according tothe circuit diagram represented in FIG. 9.

In the circuit diagram represented in FIG. 9, parasitic capacitor Cp isformed between the signal line DTL and the anode electrode (node s).Thus, when the electric potential of the signal line DTL is shifted,capacitive coupling is overlapped in the anode, that is, the source(node s) of the driving transistor 1B.

In period (I), when the signal line DTL is shifted from the video signalreference electric potential Vo to the video signal Vsig prior tosampling of the video signal, capacitive coupling occurs between thesignal line DTL and the anode electrode (node s). Accordingly, theelectric potential of the source (node s) of the driving transistor 1Brises up by an amount corresponding to a capacitance ratio from theelectric potential after completion of the threshold value correcting.Similarly, in accordance with the rise in the electric potential of thesource of the driving transistor 1B, the electric potential of the gate(node g) of the driving transistor 1B also rises up from the videosignal reference electric potential Vo by the bootstrap operation.

Next, the sampling of the video signal is started in the state in whichthe electric potential is raised up. Accordingly, not the original inputamplitude of “Vin=Vsig−Vo” but an input amplitude of “Vin=Vsig−Va”(here, Va>Vo) is input. Accordingly, the gate-to-source voltage of thedriving transistor 1B drops, whereby the luminance is decreased. Sincethe capacitive coupling during period (II) occurs in the state in whicha current flows through the organic EL element 1D, the electricpotential is returned to its original electric potential after thecapacitive coupling.

3. Configuration Example of this Embodiment System Configuration

FIG. 11 is a diagram of the system configuration representing oneexample of this embodiment. As represented in FIG. 11, an organic ELdisplay device 100 has a configuration including a pixel array unit 102formed by two-dimensionally disposing pixels (PXLC) 101 in a matrixshape and a driving unit that is disposed on the periphery of the pixelarray unit 102 and drives each pixel 101. As the driving unit thatdrives the pixels 101, for example, a horizontal driving circuit 103, awriting scanning circuit 104, and a power supply scanning circuit 105are disposed.

In the pixel array unit 102, in the pixel array of m rows and n columns,scanning lines WSL-1 to WSL-m and power supply lines DSL-1 to DSL-m arewired for each pixel row, and signal lines DTL-1 to DTL-n are wired foreach pixel column. The configuration of these components is the same asthat represented in FIG. 1.

Wiring Structure

FIG. 12 is a schematic plan view illustrating the pixel structureaccording to this embodiment. FIG. 12 represents the dispositionconfiguration of an R (red) pixel, a G (green) pixel, and a B (blue)pixel. Each pixel is configured between a power supply line DSL and ascanning line WSL that extend in the horizontal direction (thehorizontal direction in the figure), and the area of each of RGB pixelsis partitioned by the signal lines DTL extending in the verticaldirection (the vertical direction in the figure).

Within the area of each pixel, a writing transistor 1A, a drivingtransistor 1B, and a holding capacitor 1C are disposed. In addition, anauxiliary capacitor 1J that is used for adjusting a writing gain or amobility correcting time is also disposed.

In the example represented in FIG. 12, a case is shown where the patterndensity of the G (green) pixel is lower than that of the R (red) pixel,and the pattern density of the B (blue) pixel is higher than that of theR (red) pixel.

The signal lines DTL-R, DTL-G, and DTL-B are disposed at an equal pitchin the viewpoint of reflection of external light. Accordingly, a part ofthe auxiliary capacitor 1J, which is a constituent element of the B(blue) pixel, is set in the area of the adjacent G (green) pixel.

Here, the writing transistor 1A, the gate electrode of the drivingtransistor 1B, the lower electrode of the holding capacitor 1C that isconductive with the gate electrode, and the lower electrode of theauxiliary capacitor 1J are formed as the first wiring layer.

In addition, the power supply line DSL, the signal line DTL, and thescanning line WSL are formed as the second wiring layer. In addition, anintersection portion of the power supply line DSL and the signal lineDTL and an intersection portion of the signal line DTL and the scanningline WSL are switched over to the first wiring layer through a contacthole.

In addition, the writing transistor 1A, the source and drain electrodesof the driving transistor 1B, the upper electrode of the holdingcapacitor 1C that is conductive with the source electrode of the drivingtransistor 1B, and the upper electrode of the auxiliary capacitor 1J areformed of polysilicon. The polysilicon is a middle layer that isdisposed between the first wiring layer and the second wiring layer.

In the above-described wiring configuration, according to thisembodiment, the upper electrode (one electrode) of the auxiliarycapacitor 1J and the cathode electrode of the organic EL element areallowed to be conductive with each other, and the lower electrode (theother electrode) of the auxiliary capacitor 1J and the anode electrodeof the organic EL element are allowed to be conductive with each other.

In other words, in the pattern layout of the pixel structure accordingto this embodiment, when the auxiliary capacitor 1J passes the lowerside of the signal line DTL, the upper electrode (one electrode), whichis disposed on the signal line DTL side, of the electrodes of theauxiliary capacitor 1J is allowed to be conductive with the sourceelectrode of the driving transistor 1B (the anode electrode (node s) ofthe organic EL element 1D) and is set as the first wiring layer. Inaddition, the lower electrode (the other electrode) of the auxiliarycapacitor 1J is allowed to be conductive with the cathode 1H of theorganic EL element 1D and is set as the middle layer formed ofpolysilicon.

FIG. 13 is a schematic cross-sectional view taken along line B-B shownin FIG. 12. The pixel structure includes the first wiring layer M1, thesecond wiring layer M2, and the middle layer MD formed of polysiliconthat are disposed on a glass substrate. As described above, a part ofthe auxiliary capacitor 1J of the B (blue) pixel is set to be in thearea of the adjacent G (green) pixel. Thus, below the signal line DTL-B,an upper electrode D1-1J of the auxiliary capacitor 1J that is formed ofpolysilicon is disposed. In addition, in the middle layer MD formed ofpolysilicon, an upper electrode D1-1C of the holding capacitor 1C of theB (blue) pixel is disposed.

In the above-described cross-sectional structure, according to thisembodiment, the upper electrode D1-1J of the auxiliary capacitor 1J isallowed to be conductive with the cathode of the organic EL element, andthe lower electrode D2-1J is allowed to be conductive with the anode.

FIG. 14 is a schematic cross-sectional view taken along line C-C shownin FIG. 12. According to this embodiment, the node of the upperelectrode D1-1J of the auxiliary capacitor 1J and the node of the upperelectrode D1-1C of the holding capacitor 1C are different to beseparated from each other. In addition, the node of the lower electrodeD2-1J of the auxiliary capacitor 1J and the node of the upper electrodeD1-1C of the holding capacitor 1C are the same to be conductive witheach other. In order to allow the electrodes to be conductive with eachother, a contact hole CH1 is formed in the lower electrode D2-1J of theauxiliary capacitor 1J, a contact hole CH2 is formed in the upperelectrode D1-1C of the holding capacitor 1C, and the lower electrodeD2-1J of the auxiliary capacitor 1J and the upper electrode D1-1C of theholding capacitor 1C are connected to be conductive with each otherthrough a wiring D2 disposed in the second wiring layer.

By using the above-described wiring structure, even when the auxiliarycapacitor 1J is configured to pass below the signal line DTL-B, a shieldcan be configured between the signal line DTL-B and the anode (node s)by the cathode 1H. Accordingly, the parasitic capacitor Cp asrepresented in FIG. 9 is not formed between the signal line DTL-B andthe anode-side electrode of the auxiliary capacitor 1J.

Timing Chart

FIG. 15 is a timing chart illustrating the operation of the pixelconfiguration according to this embodiment. In the figure, solid linesrepresent variances in the electric potentials in the pixelconfiguration of this embodiment, and broken lines represent variancesin the electric potentials in a case where the parasitic capacitance Cprepresented in the circuit diagrams of FIGS. 4A to 4D is included.

In a case where the parasitic capacitance Cp is included, when theelectric potential of the video signal line DTL is switched, capacitivecoupling overlaps in the anode, that is, the source (node s) of thedriving transistor 1B. In period (I), when the signal line DTL isshifted from the video signal reference electric potential Vo to thevideo signal Vsig prior to sampling of the video signal, capacitivecoupling occurs between the signal line DTL and the anode (node s).Accordingly, the electric potential of the source (node s) of thedriving transistor 1B rises up by an amount corresponding to acapacitance ratio from the electric potential after completion of thethreshold value correcting. Similarly, in accordance with the rise inthe electric potential of the source of the driving transistor 1B, theelectric potential of the gate g of the N-type driving transistor 1Balso rises up from the video signal reference electric potential Vo bythe bootstrap operation.

Next, the sampling of the video signal is started in the state in whichthe electric potential is raised up. Accordingly, not the original inputamplitude of “Vin=Vsig−Vo” but an input amplitude of “Vin=Vsig−Va”(here, Va>Vo) is input. Accordingly, the gate-to-source voltage of theN-type driving transistor 1B drops, whereby the luminance is decreased.

On the other hand, according to this embodiment, the parasiticcapacitance Cp is not formed. Thus, when the electric potential of thevideo signal line DTL is switched, the capacitive coupling does notoverlap in the source (node s) of the driving transistor 1B.Accordingly, the source (node s) of the driving transistor 1B does notchange after completion of the threshold value correction. Thus, thesampling of the video signal is started in the state in which thethreshold value is corrected, and accordingly, the original inputamplitude of “Vin=Vsig−Vo” is input, whereby a decrease in the luminancerarely occurs.

In the above-described embodiment, a case where the present invention isapplied to an organic EL display device using an organic EL element asthe electro-optical element of the pixel 101 represented in FIG. 11 hasbeen described as an example. However, the present invention is notlimited to such an application and may be applied to all the displaydevices that use an electro-optical element (light emitting element) ofthe current-driven type in which the emission luminance changes inaccordance with the value of a current flowing through the device.

In addition, as the configuration of the pixel 101, a case where thepixel configuration of 2Tr/1C, in which two transistors (Tr) and onecapacitor (C) are included, is used has been described as an example.However, the present invention is not limited thereto. Thus, theinvention can be applied to a different pixel configuration such as apixel configuration of 4Tr/1C in which four transistors (Tr) and onecapacitor (C) are included.

4. Applications

The above-described display device according to this embodiment can beapplied to various electronic apparatuses, for example, as representedin FIGS. 15 to 19. For example, the above-described display device canbe used as a display device of electronic apparatuses in all the fields,in which a video signal input to the electronic apparatus or a videosignal generated in the electronic apparatus is displayed as an image ora video, such as a digital camera, a notebook personal computer, amobile terminal device including a cellular phone and the like, and avideo camera.

As described above, by using the display device according to thisembodiment as a display device of the electronic apparatuses in all thefields, the image quality of a display image can be improved.Accordingly, there is an advantage that a high-quality image display canbe performed in various electronic apparatuses.

In addition, the display device according to this embodiment includes adisplay device having a sealed configuration in a module shape. Forexample, a display module that is formed by being attached to anopposing portion of a pixel array unit 102 such as transparent glasscorresponds to such a display device. In the transparent opposingportion, a color filter, a protection film, or the like may be disposed,and the above-described light shield film may be additionally disposed.In addition, in the display module, a circuit unit used for input oroutput of a signal or the like to the pixel array unit from the outside,an FPC (flexible print circuit), or the like may be disposed.

Hereinafter, concrete examples of the electronic apparatus to which thedisplay device according to this embodiment applies will be described.

FIG. 16 is a perspective view showing the outer appearance of atelevision set to which this embodiment is applied. The television setaccording to this application includes a video display screen unit 107that is configured by a front panel 108, and a filter glass 109, and thelike. By using the display device according to this embodiment as thevideo display screen unit 107, the television set is configured.

FIGS. 17A and 17B are perspective views showing the outer appearance ofa digital camera to which this embodiment is applied. FIG. 17A is aperspective view viewed from the front side, and FIG. 17B is aperspective view viewed from the rear side. The digital camera accordingto this application includes a light emitting unit 111 for flash, adisplay unit 112, a menu switch 113, a shutter button 114, and the like.The digital camera is manufactured by using the display device accordingto this embodiment as the display unit 112.

FIG. 18 is a perspective view showing the outer appearance of a notebookpersonal computer to which this embodiment is applied. The notebookpersonal computer according to this embodiment includes a keyboard 122that is operated when a text or the like is input to a main body 121, adisplay unit 123 that displays an image, and the like. The notebookpersonal computer is manufactured by using the display device accordingto this embodiment as the display unit 123.

FIG. 19 is a perspective view showing the outer appearance of a videocamera to which this embodiment is applied. The video camera accordingto this application includes a main body unit 131, a lens 132 disposedon a side facing the front side for photographing a subject, astart/stop switch 133 that is used for photographing, a display unit134, and the like. By using the display device according to thisembodiment as the display unit 134, the video camera is manufactured.

FIGS. 20A to 20G are diagrams showing the outer appearances of a mobileterminal device, to which this embodiment is applied, such as a cellularphone. FIG. 20A is a front view in an open state, FIG. 20B is a sideview thereof, FIG. 20C is a front view in a closed state, FIG. 20D is aleft side view, FIG. 20E is a right side view, FIG. 20F is a top view,and FIG. 20G is a bottom view. The cellular phone according to thisapplication includes an upper casing 141, a lower casing 142, aconnection portion (here, a hinge portion) 143, a display 144, a subdisplay 145, a picture light 146, a camera 147, and the like. By usingthe display device according to this embodiment as the display 144 orthe sub display 145, the cellular phone is manufactured.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A display device comprising: a pixel array unit having pixelsincluding a circuit configuration, in which a first electrode of anelectro-optical element and a source electrode of a driving transistorare connected together, a gate electrode of the driving transistor and asource electrode or a drain electrode of a writing transistor areconnected together, a holding capacitor is connected between the gateelectrode and the source electrode of the driving transistor, and anauxiliary capacitor is connected between the first electrode and asecond electrode of the electro-optical element, disposed in a matrixshape, wherein, a signal line used for transmitting a video signal isdisposed between adjacent pixels, and from one pixel of adjacent pixelsto an area of the other pixel, the auxiliary capacitor of the one pixelis set to be disposed, and one electrode of the auxiliary capacitor thatis disposed on the signal line side is conductive with the secondelectrode of the electro-optical element.
 2. The display deviceaccording to claim 1, wherein the gate electrode of the drivingtransistor and the other electrode of the auxiliary capacitor aredisposed in a first wiring layer, the signal line is disposed in asecond wiring layer, and the one electrode of the auxiliary capacitor isdisposed in a middle layer that is disposed between the first wiringlayer and the second wiring layer.
 3. The display device according toclaim 2, wherein the middle layer is formed of polysilicon.
 4. Thedisplay device according to any one of claims 1 to 3, wherein theelectro-optical element is an organic EL (Electroluminescence) element,the first electrode is an anode electrode, and the second electrode is acathode electrode.
 5. An electronic apparatus comprising: a displaydevice disposed in a main body casing, the display device including apixel array unit having pixels including a circuit configuration, inwhich a first electrode of an electro-optical element and a sourceelectrode of a driving transistor are connected together, a gateelectrode of the driving transistor and a source electrode or a drainelectrode of a writing transistor are connected together, a holdingcapacitor is connected between the gate electrode and the sourceelectrode of the driving transistor, and an auxiliary capacitor isconnected between the first electrode and a second electrode of theelectro-optical element, disposed in a matrix shape, wherein, a signalline used for transmitting a video signal is disposed between adjacentpixels, and, from one pixel of adjacent pixels to an area of the otherpixel, the auxiliary capacitor of the one pixel is set to be disposed,and one electrode of the auxiliary capacitor that is disposed on thesignal line side is conductive with the second electrode of theelectro-optical element.